Straightforward trunking system



- Nov. 29, 1927. 1,650,683

H. M. BASCOM ET AL STRAIGHTFORWARD TRUNKING SYSTEM Filed Sept. 1925 OFFICE I INTERMEDIATE OFFICE OFFICE Z SIB FIRST TR'uNK by A27)? Patented NW. 29,1927,

u rrun STATES PATENT curios,

HENRY M. BASCOM, OF BROOKLYN, AND CLARENCE B. FOWLER, OF QUEENS, NEW

YORK; SAID BASOOM ASSIGNOR TOAMERIOAN TELEPHONE AND TELEGRAPH COM- EANY, A CORPOBATIONOF NEW YORK, AND $AID FOWLER ASSIGNOR TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF N EW YORK, N. Y., A CORPORATION OF NEW YORK.

STRAIGHTFORWARI) TRUNKING Application filed September 17, 1925. Serial No. 56,871.

This invention relates to telephone systems and more particularly to a service measuring arrangement for straightfor-- ward trunking systems.

5 In systems of-this type automatically operated switches are often employed at an intermediate oiiice in extending connections between groups of trunk lines incoming to this otfice from a number of small oiiices to 0 a common group 'of trunk lines leading from this intermediateoffice to a distant ofiice and it is with straight-forward trunking systems of this class that this invention is concerned.

5 An object of this invention is to provide a greatly simplified service measuring or message registering system for use in sys tems of this class whereby a record is made of the number of times the trunk lines outgoing to a distant otficeare engaged.

To attain this and other objects of the invention as will hereinafter appear, there is provided in accordance with'one feature of the'invention, a relay for each outgoing trunk which is operated the moment said trunk is engaged through an automatic switch by a trunk incoming to the intermediate oiiice, a common meter of the type that registers on its operation and a contact and armature arrangement on said relays in combination with a circuit arrangement therefor whereby when any one of said relays is operated, a partial registration is efiected on the meter regardless of the position of the meter atthe time said relay operated; that is, regardless of whether it is in operated or released position and whereby when any one of said relays is released,the second part of the registrations is efiected on the meter regardless of its position at the time the release of the relay takes place.

The, advantage of this service measuring arrangement is that arninimum amount of apparatus is required and that a positive registration is effected regardless of the order in which the trunks outgoing to a distant oitice become engaged.

This invention has'been illustrated in the accompanying drawing in connection with a straight-forward trunking system in which the operators at different oflioes such as ofiice 1 and oilice 2 have access through a plurality of trunks such as 3 from office 1 and from different smaller offices have accessto a common group of trunks outgoing to a distant oilice, said outgoing trunks being smaller in number than the total number of incoming trunks.

In systems of this class, as in any other system, of similar nature, it is essential to keep accurate record of the number of times the outgoing trunks are engaged, and con-v sidering that the outgoing trunks are mul tipled to a larger number of switches which are operated in no particularorder but as the incoming trunks at the intermediate ex- I change happen to become engaged by the operators at the various smaller oflices the problem of accomplishing this purpose becomes a complicated and difficult one. However, in accordance with this invention this has been done w th the least possible amount of apparatus as Sl'lOWIllIl the accompanying drawing and" consists primarily of a series of relays such as relays 50, 51, 52 and 53,

the meter or message register 54 and a circult arrangement controlled by the armatures and contacts of'these relays.

In describing this invention, asit is applied to a systemof this kind, the operation of extending a connection from office 1 through trunkg, switch 10 and an idle outgoing trunk will be described followed by a message register itself regardless of the on der 111 which outgoing trunks are engaged.

.If it, is assumed then that an operator at a I I e o description of the registration of a call over:

an outgoing trunk and the function of the position in office 1 inserts thecalling plug of e a cord circuit into jack 2, for example,..it is well known in the art that the tip terminal of jack 2 will be connected to ground and a circuit will therefore be established as follows: battery, upper inake-hefore-break contact of relay 20, upper winding of relay 21, tip conductor of trunli line 3, tipterniinal of jack 2, to ground at the operators cord eircuit. This causes the operation of relay 21 which in attracting its armature closes a circuit'fo'r relay-22 follows: battery, armature and front "contact of; relay 21, lower make-before-break contacts of relay 20, uper winding of relay 22 to ground. This causes the operation ofrelay 22 whichin attracting its upper armatiirs opens" the up and ring conductors to the switch to prevent interference with a possible 'otlier connection over the outgoing trunks terminating at 'lilii's switch, The operation of relay 22 also'closesa circuit for relay as follows: batt ariiiat'ure and front contact of relay 21', wer inner armature and front contact "of an 22', winding of relay 20 to ground.

Rel'ay'20 in operatingcloses a locking ciredit for itself through its lower middle armature and front c'oiitact to thebattery at the arinatiir'e and front contact of relay 21 1 and also connectsat its upper armature and front'coii'tact iiiicl lower inner armature and frontfco'i'i'tact' the tip and ring leads from .triinkline 3 tocontacts of relay The operati'oii' of relay 20 opens the circuit for the upper winding of relay 22 but the circuit for the lower winding of this relay 22 is new extended from the battery at the arriizi'turQhIid front contact of relay 21, tlirbugi this windin tiie lower outer armature and frontfcont'act of relay 22 to the hunting brush 25 of switch 10., It should be noted that a parallel pathis alsoestablished to the huntiii'g h'r'ush fo'r the stepping magnet 26 iroi n' the battery at v the armature and A fron cont'act 'rel'aj 21:, through the lower miiemnmaaae and front'contactot relay 22, the switch 10 is resting, with its bru'shes o'iii a busy outgoing trunk, ground a semi, steers lead of this*t'ru'iik through the'JiminiiQg b'ru'sh, 25 is supplied for the maintenance of rela" 22 energized. The same groui'idcauses tie stepping magnet 26 to; ape-meme in operating interrupts its own'ci'rcuitso that it will release and stop the brushes' of si'vit'ch 10 on to the next t1'ii-nkfterniin'als. In case the next trunk is also and consequently has its sleeve lead grounded, the switch operates again and thi'sac tion is repeated until t'he' brushes fiaally come to rest on the terminal of an 'trii nlt. 'lheli'untiii'g brush 25 is so constriifcted. as not to'opei'i the circuit to the sleeve terminals when stepping from one terminal toanoth'er and the circuit for the lower windiiigofr'elay'22 is therefore maintai'lie'd until the trunk is re'acl'ied. W'hen the switch l'tl th erefore comes to rest on aiiitlle outgoing trunk, the sleeve circuit through the lower winding 'ofrelay 22 'is broken so that this relay in releasing now completes the connection of the tip and ring conductors from the trunk line 3 through to the tip and ringbrushes 27 and 28 of switch 10. It should also be noted that a busy condition is now established on the sleeve teriiiinal of this trunk from ground at the lower outer armature and front contact ot relay 2O through the lower outer-armature and back coiitact of relay 22 through brush 25 sothat the selected trunk will new test easy to other switches to which its terminals are iiiul'tipl'ed. lVheii relay 22 releases, the condition will therefore be such that relay 21 will he maintained energized by having its two windings included in the tip and ring leads of this, trunk line 3,. and consequently,

relay 20 will also he held locked by virtue of the operation of relay 21., l p h Referring now to the registration of the engagement of the trunks outgoing from the intermediate oiiice, it will be noted that on each engagement of aii outgoing trunk a; correspondingrelay such as 50, 51, 52 or 53 is energized through the sleeve terminals of a corres 'iondingly engaged switch' such as 10 or 15 to cause the operation or release of the meter 54 depending on its previouscondition. If, for example, relay 50 is energized due to engagement of trunk 30 and the meter 5% iii non-operated condition, that is, if all of the other relays such as 51, 52, 53 are in normal position, a circuit will be closed as follows; battery, winding of the Dieter 5 4", inner arinatii'res and back contacts of relays 53, 52 and 51 in series and arinatures and iroiit contacts of relay to ground. That is in this case the engagement of trunk 30, is

recorded by the operation of meter 54. If,

on the other hand, for example, relay 51 is operated due to the engagement or trunk 450 attlieftinie relay 50 operates, it will be seen that the meter 54 has already been operated over the followingcircuit: battery, winding of meter 54', inner arn'iatur'es and back contacts of rel'ays 53 and 52,, outer arii'i'atiire and front -contact of relay 51', a maiures and iln gagement of the trunk corresponding to the sleeve lead 55 and relays 51 and 535m in normal position when relay 50 is energiz i'd, the nieter 5 l will then have been operated over the following circuit battery winding of meter 54, inner armature and 'ack contact of relay 53, outer armature and front contact of relay 52, outer armature and back contact of relay 51, armatures and back contacts of relay to ground so that when relay 50 now operates, this circuit will be broken at the armature and back contacts of relay 50 and the meter 54 permitted to release so that the engagement of trunk 30 in this case is similarly identified by a release of the meter. The same operation also will takeplace if relay 53 only is energized at the time relay 50 becomes operated, and to mention still a further example of this circuit, if all the relays 51, 52 and 53 and any other relays in the group are energized when relay 50 operates, the release or opera tion of meter 54 will take place. 7

No matter, therefore what relay in the group would operate, the meter 54 would change from its previous condition to parti-ally record the engagement of a trunk and on the release of a relay the meter would also change from its previous position so as to partly record the engagement of a trunk. That is, the arrangement may be considered as having recorded each single engagement of a trunk by causing two effects on the meter, whether or not these are both releases of both operations of the meter or a release and an operation is immaterial, for in the end when a number of trunks have been engaged and then become idle a number of times, the meter would have operated the corresponding number of times the various trunks had been engaged. It is therefore seen that an ordinary meter making a record each time it is operated may be used in this system.

What is claimed is:

1. In a trunking system, incoming lines, a smaller number of outgoing lines, switching means associated with each incoming line for extending it'to an outgoing line, a relay for each outgoing line and a meter ing means common to said relays, said metering means being responsive to a change in condition of one of said relays to operate and to a subsequent change in condition of one of said relays to release. I

2. In a trunking system, incoming lines, a smaller number of outgoing lines, switching means associated with each incoming line for extending it to an outgoing line, a relay for each of said outgoing lines responsive to the engagement of the corresponding outgoing line and a metering means common to said relays, saidmetering means be ing responsive to a change in condition of one of said relays to operate and to a subsequent change in condition of one of said relays to release.

3. In a trunking system, incoming lines, a smaller number of outgoing lines, switching means associated with each incoming line for extending it to an outgoing line, a relay for each of said outgoing lines, a meter adapted to register eachtime it is actuated and means associated with said relays and the meter for effecting the operation or release of said meter each time a relay is actuated and each time a relay is released. I

4:. In a trunking system, incominglines, a smaller number of outgoing lines, a switching means associated with each incoming line for extending it to an outgoing line,

relays associated with all'of said switching means and one of said relays associated with each outgoingline, means responsive to the operation of any one of said switching means for operating the relay corresponding to the outgoing line selected by said switching means, means responsive to the release of any one of said switching means for releasing the relay corresponding to the outgoing line to which the switching means is extended, a metering device arranged to register only on its operation and a circuit connecting the metering device and said relays so arranged that each time a relay is operated or released the metering device is either operated or released depending on its previous condition so that a registration takes place on the meter foreach use of an outgoing line.

5, In a trunking system, incoming lines, a

smaller number of outgoing lines, switching means associated. with each incoming line for extending it to an outgoing line and means for registering each use of each out going line comprising a plurality of relays one individual to each outgoing line, a metering device and a circuit arrangement associated with said relays and said metering device for actuating or releasing said Vmeter, depending upon its previous condition, each time a relay is actuated or released.

In witness whereof, I hereunto subscribe my name this 31st day of August, A. D.,

HENRY M. BASCOM.

In witness whereof, I hereunto subscribe my name this 9th day of September, 1925.

CLARENCE B. FOWLER. 

